1. Field of the Invention
This invention relates to a pattern recognition method. More particularly, the invention relates to a method and apparatus for on-line recognition of a handwriting pattern, in which a pattern sequence inputted by handwriting in real-time is recognized upon being delimited pattern by pattern.
2. Description of the Prior Art
In the prior art, a pattern recognition apparatus such as an on-line, handwritten character recognition apparatus comprises a resistance-film digitizer serving as coordinate input means for inputting handwriting patterns; one of (a) pattern delimiting means for delimiting a pattern by measuring the period of time (hereinafter referred to as "pen-up time") a pen has been raised from the digitizer, (b) pattern-entry blocks for delimiting a pattern based upon the absolute position at which the pattern is entered, and (c) a recognition-execute key for inputting the end of entry of one pattern; and pattern recognizing means for performing recognition by matching coordinate information relating to one entered pattern with a dictionary of individual patterns.
In the example of the prior art described above, however, certain problems arise when it is desired to enter patterns in succession and the delimiting of the individual patterns is to be performed by measuring pen-up time, by using the pattern-entry blocks or by means of the recognition-execute key. Specifically, the problems encountered are as follows:
(1) Assume that a pattern is considered delimited when a fixed period of time has elapsed when measuring pen-up time. If the fixed period of time is made comparatively long, then the person doing the writing is constrained to wait a comparatively long period of time between entry of individual patterns. If the fixed period of time is made comparatively short, on the other hand, then the pen-up time between the first and second strokes of one and the same pattern must be made shorter than the aforementioned fixed period of time. Since this does now allow enough time for a pattern to be entered in a natural manner, cases arise in which pattern delimiting is performed erroneously.
(2) In the case where use is made of the pattern-entry blocks in which delimiting of an entered pattern is performed based upon absolute position, patterns cannot be entered at freely selected positions and care must be taken to assure that each individual pattern does not protrude from the block. As a result, when patterns are entered in a free, natural manner, erroneous delimiting of the patterns can occur.
(3) In the case where pattern delimiting is performed by pressing a recognition-execute key each time entry of one pattern ends, the key must be pressed after every single pattern is entered. This is a very troublesome operation.